U.S. patent application number 13/803181 was filed with the patent office on 2013-10-17 for methods and apparatus for generating and delivering a process gas for processing a substrate.
The applicant listed for this patent is APPLIED MATERIALS, INC.. Invention is credited to DAVID K. CARLSON, ERROL ANTONIO C. SANCHEZ.
Application Number | 20130269613 13/803181 |
Document ID | / |
Family ID | 49261112 |
Filed Date | 2013-10-17 |
United States Patent
Application |
20130269613 |
Kind Code |
A1 |
SANCHEZ; ERROL ANTONIO C. ;
et al. |
October 17, 2013 |
METHODS AND APPARATUS FOR GENERATING AND DELIVERING A PROCESS GAS
FOR PROCESSING A SUBSTRATE
Abstract
Methods and apparatus for generating and delivering process
gases for processing substrates are provided herein. In some
embodiments, an apparatus for processing a substrate may include a
container comprising a lid, a bottom, and a sidewall, wherein the
lid, the bottom, and the sidewall define an open area; a solid
precursor collection tray disposed within the open area; a gas
delivery tube disposed within the open area and extending toward
the solid precursor collection tray to provide a gas proximate the
solid precursor collection tray; and a purge flow conduit coupled
to the open area.
Inventors: |
SANCHEZ; ERROL ANTONIO C.;
(Tracy, CA) ; CARLSON; DAVID K.; (San Jose,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
APPLIED MATERIALS, INC. |
Santa Clara |
CA |
US |
|
|
Family ID: |
49261112 |
Appl. No.: |
13/803181 |
Filed: |
March 14, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61617877 |
Mar 30, 2012 |
|
|
|
Current U.S.
Class: |
118/724 ;
118/715 |
Current CPC
Class: |
C23C 16/4488 20130101;
C30B 29/40 20130101; C30B 25/08 20130101; H01L 21/02104 20130101;
C23C 14/246 20130101; H01L 21/67017 20130101 |
Class at
Publication: |
118/724 ;
118/715 |
International
Class: |
H01L 21/02 20060101
H01L021/02 |
Claims
1. An apparatus for processing a substrate, comprising: a container
comprising a lid, a bottom, and a sidewall, wherein the lid, the
bottom, and the sidewall define an open area; a solid precursor
collection tray disposed within the open area; a gas delivery tube
disposed within the open area and extending toward the solid
precursor collection tray to provide a gas proximate the solid
precursor collection tray; and a purge flow conduit coupled to the
open area.
2. The apparatus of claim 1, wherein the apparatus further
comprises a precursor delivery tube disposed within the open area
and extending toward the solid precursor collection tray.
3. The apparatus of claim 2, wherein the precursor delivery tube
further comprises: a first end coupled to an precursor dispenser;
and a second end disposed above a storage area of the solid
precursor collection tray.
4. The apparatus of claim 3, wherein the precursor dispenser
further comprises: a removable hopper comprising a hopper container
and least one of a plug valve or a ball valve coupled to a bottom
of the hopper container; a fill port, wherein the removable hopper
is fitted to the fill port; a rotatable precursor dispenser coupled
to the fill port; and a first gas supply coupled to the rotatable
precursor dispenser.
5. The apparatus of claim 4, wherein the hopper container is made
of quartz.
6. The apparatus of claim 4, wherein the rotatable precursor
dispenser is coupled to the precursor delivery tube.
7. The apparatus of claim 4, wherein the first gas supply is a
nitrogen gas supply.
8. The apparatus of claim 1, wherein the container is made of
quartz.
9. The apparatus of claim 1, wherein the apparatus further
comprises a gas dispersion plate coupled to the bottom of the
container.
10. The apparatus of claim 9, wherein the gas dispersion plate
further comprises a plurality of holes arranged in a desired
pattern to disperse the gas flowing through the gas dispersion
plate.
11. The apparatus of claim 1, wherein the solid precursor
collection tray further comprises: an outer wall; a floor coupled
to the outer wall, wherein the floor and the outer wall define a
storage area of the solid precursor collection tray; a radiant
heater circumscribing the outer wall; and a baffle disposed within
the storage area.
12. The apparatus of claim 11, wherein the outer wall, floor, and
baffle are made of quartz.
13. The apparatus of claim 11, wherein the outer wall further
comprises a plurality of holes.
14. The apparatus of claim 11, wherein the radiant heater is made
of silicon carbide.
15. The apparatus of claim 11, wherein the solid precursor
collection tray further comprises: a plurality of heating lamps
circumscribing the radiant heater; a plurality of windows disposed
within the radiant heater; and a plurality of sensors
circumscribing the windows to detect at least one of a temperature
of the radiant heater or a level of the precursor disposed on the
precursor collection tray.
16. The apparatus of claim 15, wherein the plurality of sensors
comprise a pyrometer and a precursor level sensor.
17. The apparatus of claim 11, wherein the baffle further comprises
a plurality of slots to allow a gas from a second gas source to
enter the storage area.
18. The apparatus of claim 17, wherein the gas delivery tube
further comprises: a first end coupled to the second gas source; a
second end disposed though a hole in a top of the baffle; a
plurality of holes within the second end to allow the gas from the
second gas source to escape the gas delivery tube; and a silicon
carbide tube disposed within the gas delivery tube.
19. The apparatus of claim 18, wherein the second gas source
provides a gas comprising at least one of hydrogen, nitrogen,
hydrogen chloride, or chlorine.
20. The apparatus of claim 1, wherein the gas delivery tube is made
of quartz.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. provisional patent
application Ser. No. 61/617,877, filed Mar. 30, 2012, which is
herein incorporated by reference in its entirety.
FIELD
[0002] Embodiments of the present invention generally relate to
semiconductor processing equipment.
BACKGROUND
[0003] The inventors have observed that conventional Group III-V
deposition processes typically use hydride sources and
organo-metallic sources that are difficult to handle safely due to
the high flammability and/or high toxicity of these sources. In
addition, the use of certain organo-metallic sources for such
processes requires complex and expensive delivery systems. The
inventors have further observed that conventional systems used to
form gaseous precursors from solid state materials typically
utilize pre-filled sealed ampoules to contain the solid state
materials during the evaporation/sublimation process. However, when
the solid state material contained within the pre-filled ampoules
become exhausted the pre-filled ampoule must be removed from the
process chamber and replaced, thus leading to process downtime.
Moreover, the inventors have discovered that when using pre-filled
ampoules the solid state material may pack unevenly during
transportation or installation, thus leading to non-uniform gas
movement or gas channeling through the solid state material,
thereby causing a non-uniform formation and/or dispersion of
gaseous precursor.
[0004] Therefore, the inventors have provided improved methods and
apparatus for generating and delivering process gases for
processing substrates.
SUMMARY
[0005] Methods and apparatus for generating and delivering process
gases for processing substrates are provided herein. In some
embodiments, an apparatus for processing a substrate may include: a
container comprising a lid, a bottom, and a sidewall, wherein the
lid, the bottom, and the sidewall define an open area; a solid
precursor collection tray disposed within the open area; a gas
delivery tube disposed within the open area and extending toward
the solid precursor collection tray to provide a gas proximate the
solid precursor collection tray; and a purge flow conduit coupled
to the open area.
[0006] Other and further embodiments of the present invention are
described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Embodiments of the present invention, briefly summarized
above and discussed in greater detail below, can be understood by
reference to the illustrative embodiments of the invention depicted
in the appended drawings. It is to be noted, however, that the
appended drawings illustrate only typical embodiments of this
invention and are therefore not to be considered limiting of its
scope, for the invention may admit to other equally effective
embodiments.
[0008] FIG. 1 depicts a process chamber having an apparatus for
generating and delivering a process gas suitable for processing a
substrate in accordance with some embodiments of the present
invention.
[0009] FIG. 2 depicts a schematic side view of a portion of an
apparatus for generating and delivering a process gas in accordance
with some embodiments of the present invention.
[0010] FIG. 3 depicts a schematic side view of a portion of an
apparatus for generating and delivering a process gas in accordance
with some embodiments of the present invention.
[0011] FIG. 4 depicts a schematic top view of a portion of an
apparatus for generating and delivering a process gas in accordance
with some embodiments of the present invention.
[0012] FIGS. 5-7 respectively depict schematic side views of a
portion of an apparatus for generating and delivering a process gas
in accordance with some embodiments of the present invention.
[0013] FIGS. 8A-B respectively depict schematic side and top views
of a gas dispersion plate suitable for use with an apparatus for
processing a substrate in accordance with some embodiments of the
present invention.
[0014] FIGS. 9A-B respectively depict schematic side and top views
of a gas dispersion plate suitable for use with an apparatus for
processing a substrate in accordance with some embodiments of the
present invention.
[0015] FIGS. 10A-B respectively depict schematic side and top views
of a gas dispersion plate suitable for use with an apparatus for
processing a substrate in accordance with some embodiments of the
present invention.
[0016] To facilitate understanding, identical reference numerals
have been used, where possible, to designate identical elements
that are common to the figures. The figures are not drawn to scale
and may be simplified for clarity. It is contemplated that elements
and features of one embodiment may be beneficially incorporated in
other embodiments without further recitation.
DETAILED DESCRIPTION
[0017] Methods and apparatus for generating and delivering process
gases for processing substrates are provided herein. In some
embodiments, the inventive apparatus may advantageously provide
source materials (e.g. solid state precursors) necessary to perform
desired deposition processes while reducing or eliminating exposure
of the operator to the toxic materials, thus increasing the safety
and efficiency of the process. Embodiments of the inventive
apparatus may further advantageously provide an automatic feed of
the source materials, thereby reducing system downtime by providing
the solid state precursor in substantially constant amounts and by
reducing exposure of the solid state precursor to contaminants,
thus maintaining a high purity of the solid state precursor.
Although not limiting in scope, the apparatus may be particularly
advantageous in applications such as epitaxial deposition of Group
III-V semiconductor materials, for example, arsenic (As) containing
materials.
[0018] FIG. 1 depicts a schematic side view of a process chamber
100 in accordance with some embodiments of the present invention.
In some embodiments, the process chamber 100 may be modified from a
commercially available process chamber, such as the RP EPIC.RTM.
reactor, available from Applied Materials, Inc. of Santa Clara,
Calif., or any other suitable semiconductor process chamber adapted
for performing deposition processes. It is contemplated the
embodiments of the present invention may also be used with process
chambers available from other manufacturers, and well as in
connection with process chambers configured for other types of
processes where sublimation or evaporation of a source material to
provide a process gas is desired.
[0019] The process chamber 100 generally comprises a chamber body
110, a temperature-controlled reaction volume 101, one or more gas
distribution mechanisms (top gas injector 170 and a side gas
injector 114 shown) and a heated exhaust manifold 118. The process
chamber 100 may further include support systems 130, and a
controller 140, as discussed in more detail below.
[0020] The chamber body 110 generally includes an upper portion
102, a lower portion 104, and an enclosure 120. The upper portion
102 is disposed on the lower portion 104 and includes a chamber lid
106 and an upper chamber liner 116. In some embodiments, an upper
pyrometer 156 may be provided to provide data regarding the
temperature of the processing surface of the substrate during
processing. Additional elements, such as a clamp ring disposed atop
the chamber lid 106 and/or a baseplate on which the upper chamber
liner may rest, have been omitted from the figure, but may
optionally be included in the process chamber 100.
[0021] The chamber lid 106 may have any suitable geometry, such as
flat (as illustrated) or having a dome-like shape. Other shapes,
such as reverse curve lids are also contemplated. In some
embodiments, the chamber lid 106 may comprise a energy reflective
material, such as quartz or the like. Accordingly, the chamber lid
106 may at least partially reflect energy radiated from the
substrate 125 and/or from lamps disposed below a substrate support
124 for supporting the substrate 125. The upper chamber liner 116
may be disposed above the injector 114 and heated exhaust manifold
118 and below the chamber lid 106, as depicted. In some embodiments
the upper chamber liner 116 may comprise an energy reflective
material, such as quartz or the like, for example, to at least
partially reflect energy as discussed above. In some embodiments,
the upper chamber liner 116, the chamber lid 106, and a lower
chamber liner 131 (discussed below) are fabricated from quartz,
thereby advantageously providing a quartz envelope surrounding the
substrate 125.
[0022] The lower portion 104 generally comprises a baseplate
assembly 119, a lower chamber liner 131, a lower dome 132, the
substrate support 124, a pre-heat ring 122, a substrate lift
assembly 160, a substrate support assembly 164, a heating system
151, and a lower pyrometer 158. The heating system 151 may be
disposed below the substrate support 124 to provide heat energy to
the substrate support 124. In some embodiments, the heating system
151 may comprise one or more outer lamps 152 and one or more inner
lamps 154. Although the term "ring" is used to describe certain
components of the process chamber, such as the pre-heat ring 122,
it is contemplated that the shape of these components need not be
circular and may include any shape, including but not limited to,
rectangles, polygons, ovals, and the like. The lower chamber liner
131 may be disposed below the injector 114 and the heated exhaust
manifold 118, for example, and above the baseplate assembly 119.
The injector 114 and the heated exhaust manifold 118 are generally
disposed between the upper portion 102 and the lower portion 104
and may be coupled to either or both of the upper portion 102 and
the lower portion 104.
[0023] The one or more gas distribution mechanisms (top gas
injector 170 and the side gas injector 114 shown) may be disposed
about the process chamber 100 in any manner suitable to provide one
or more process gases to a desired area of the reaction volume 101
to facilitate performing a desired process on the substrate 125.
For example, in some embodiments, the side gas injector 114 may be
disposed on a first side 121 of the substrate support 124 disposed
inside the chamber body 110 to provide one or more process gases,
across a processing surface 123 of a substrate 125 when the
substrate is disposed in the substrate support 124. Alternatively,
or in combination, in some embodiments, the top gas injector 114
may be disposed above the substrate 125 to provide one or more
process gases directly to the processing surface 123 of a substrate
125.
[0024] Each of the one or more gas distribution mechanisms may
provide the same, or in some embodiments, a different process gas
to the reaction volume 101. The inventors have observed that
providing the process gases via separate injectors allows the
process gases to reach the desired area of the reaction volume 101
(e.g., proximate the processing surface 123 of the substrate 125)
without reacting with one another. For example, in embodiments
where an epitaxial deposition process is performed to deposit a
Group III-V semiconductor material, the top gas injector 170 may
provide a first process gas comprising a Group V element (e.g.,
arsenic (As), phosphorous (P), or the like). In such embodiments,
the side gas injector 114 may provide a second process gas
comprising a Group III element (e.g., boron (B), aluminum (Al),
gallium (Ga), or the like) or a Group III metal-organic precursor
(e.g., triethyl or trimethyl species, such as Trimethylgallium
(Me.sub.3Ga, TMGa), Trimethylaluminum (Me.sub.3Al, TMA) and
Trimethylindium (Me.sub.3In, TMIn), or the like. In some
embodiments, the first process gas and/or second process gas may
optionally comprise at least one of a carrier gas (e.g. a hydrogen
containing gas, a nitrogen containing gas, or the like) or a halide
gas (e.g., chlorine gas (Cl2) or hydrogen chloride (HCl), or the
like).
[0025] The inventors have observed that conventional Group III-V
deposition processes typically use hydride sources such as arsine
(AsH.sub.3) and phosphine (PH.sub.3) and organo-metallic compounds
such as tertiarybutylarsine (TBA) and tertiarybutylphosphine (TBP).
However, arsine (AsH.sub.3) and phosphine (PH.sub.3) are difficult
to handle safely due to the high flammability and high toxicity of
both compounds. In addition, the use of tertiarybutylarsine (TBA)
and tertiarybutylphosphine (TBP) in such processes require complex
and expensive delivery systems.
[0026] Accordingly, in some embodiments, the process chamber 100
may comprise an apparatus 181 configured to provide a gaseous
precursor from a solid state precursor. By utilizing the apparatus
181, the inventors have observed that gaseous precursors (e.g.,
elemental, hydride based, chloride based, or the like) for the
above discussed deposition processes may advantageously be produced
in situ, thereby reducing or eliminating exposure of the operator
to the toxic materials and increasing the safety and efficiency of
the processes. In addition, in embodiments where an arsenic (As)
solid state precursor is utilized, the low vapor pressure of
arsenic (As) may advantageously provide an immediate stoppage of
arsenic (As) flow at the conclusion of the process, thereby
limiting exposure of the operator to arsenic (As) containing gases
and further enhancing the safe operation of the process chamber
100.
[0027] In some embodiments, for example as shown in FIG. 1, the
apparatus 181 may be integrated with the top gas injector 170. In
such embodiments, the apparatus 181 may be disposed within a
conduit 171 disposed within a through hole 175 of the chamber lid
106. In some embodiments, one or more mechanisms to provide process
resources, for example, such as a gas supply 179 and a solid state
precursor source 173 may be coupled to the apparatus 181. When
present, the solid state precursor source 173 may advantageously
feed material to the apparatus 181 continuously as needed, thereby
decreasing downtime that would otherwise be necessary to manually
provide the necessary materials for the process.
[0028] Referring to FIG. 2, in some embodiments, the top gas
injector 170 may comprise a reactor 204. In some embodiments the
reactor 204 may be dome-shaped, although other geometries may also
be utilized. In such embodiments, the apparatus 181 may be disposed
in an upper neck 225 of the reactor 204. In some embodiments, a
disk 232 may be disposed within the upper neck 225 above the
apparatus 181 to facilitate control over the temperature within the
upper neck 225. The disk 232 may be fabricated from, for example,
quartz (SiO.sub.2), such as opaque quartz. The thickness of the
disk 232 may be controlled and/or the addition of an inert
reflective material may be added to facilitate controlling the
temperature within the upper neck 225.
[0029] Alternatively, or in combination, a sleeve 230 fabricated
from, for example silicon carbide (SiC) may be disposed about the
upper neck 225 to provide control over a temperature within the
upper neck 225 to prevent condensation. For example, if heat losses
are too high, the sleeve 230 may comprise a thermally insulative
material in order to retain more heat. Alternatively, if the
temperature is too high, the sleeve may comprise cooling fins or
the like to facilitate the removal of heat. The disk 232 and/or the
sleeve 230 may be included to minimize heat losses to the outside
and to prevent condensation of precursors that may back diffuse.
Advantageously, no active control over the temperature is
required.
[0030] In some embodiments, a housing 216 may be disposed about the
reactor 204 to provide structural support and maintain the process
environment within the process chamber. The housing 216 may
comprise a flat or dome shape. In such embodiments, the housing 216
may comprise one or more reflecting surfaces (one reflecting
surface 206 shown) to facilitate rapid and/or uniform heating of
the reactor 204. In some embodiments, the housing 216 may comprise
one or more first ports (one first port 222 shown) to allow a flow
of air proximate an upper portion 220 of the reactor 204 that, in
some embodiments, may be utilized to cool the upper portion 220. By
air cooling the upper portion 220 of the reactor 204, the inventors
have observed that unwanted deposition on the surfaces of the
reactor 204 may be reduced or eliminated. Alternatively, or in
combination, in some embodiments, the housing 216 may comprise one
or more second ports (one second port shown 224) configured to
accommodate a heating lamp 228. When present, the heating lamp 228
may facilitate control over the temperature of the reactor 204.
[0031] In some embodiments, a baffle (shown in phantom at 214) may
be disposed within the reactor 204 to further facilitate control
over the concentration distribution of the precursor. The reactor
204 may be fabricated from materials suitable to allow heating of
the apparatus 181 and monitoring of parameters within apparatus 181
via one or more monitors (e.g., detector module 212) disposed
proximate a portion of the reactor 204. In some embodiments, the
apparatus 181 may be heated via radiant heat from a heat source
(e.g., heating module 210), although other forms of heating may be
utilized. In some embodiments, the reactor 204 may be fabricated
from quartz. In some embodiments, the reactor 204 may include a
distribution plate 218 (described below) configured to provide the
precursor to a desired area within the process chamber.
[0032] The gas distribution plate 218 may be configured to provide
a concentration of the gaseous precursor to a desired area of a
process chamber or substrate being processed in the process
chamber. For example, in some embodiments, the gas distribution
plate 218 may comprise a plurality of gas distribution holes 802
disposed proximate a peripheral edge 804 of the gas distribution
plate 218, such as shown in FIGS. 8A-B. In such embodiments, one or
more gas distribution holes 802 may be disposed proximate a center
806 of the gas distribution plate 218. In another example, in some
embodiments, the gas distribution plate 218 may be configured
asymmetrically, having the gas distribution holes 802 disposed
proximate a first side 902 of the gas distribution plate 218, such
as shown in FIGS. 9A-B. In another example, in some embodiments the
gas distribution plate may be configured such that the gas
distribution holes 802 are concentrated proximate a center 1002 of
the gas distribution plate 218 with no gas distribution holes
disposed proximate a peripheral edge 1004 of the gas distribution
plate 218, such as shown in FIGS. 10A-B.
[0033] Referring to FIG. 3, the apparatus 181 may generally
comprise a container 302, one or more solid precursor collection
trays (two solid precursor collection trays 312 shown), one or more
material delivery tubes (two material delivery tubes 308, 306
shown) to provide the solid state precursor to the one or more
solid precursor collection trays 312, and a gas delivery tube 304
to provide a gas to the one or more solid precursor collection
trays 312.
[0034] The container 302 generally comprises a lid 334, bottom 332
and sidewall 336, wherein the lid 334, bottom 332 and sidewall 336
define an inner volume 338. The container 302 may be fabricated
from any suitable material that is non reactive with the solid
state or gaseous precursor disposed therein while allowing heating
of the inner volume 338 via radiant heat from a heat source (e.g.,
heating module 210) and the monitoring of parameters within
apparatus 181 via one or more monitors (e.g., detector module 212)
disposed proximate a portion of the reactor 204. In some
embodiments, the container 302 may be fabricated from quartz
(SiO.sub.2).
[0035] In some embodiments, the lid 334 may comprise a plurality of
through holes 338 configured to allow one or more conduits or tubes
(e.g., gas delivery tube 304, a purge flow tube 310, material
delivery tubes 306, 308, or the like) to pass through the lid 334.
In some embodiments, the container 302 may comprise an inwardly
facing flange 346 configured to support a baffle 348. The baffle
348 comprises a plurality of through holes 350 configured to allow
the one or more tubes to pass through the baffle 348. When present,
the inwardly facing flange 346 and/or baffle 348 support the one or
more tubes, maintaining the one or more tubes in a desired
position. The baffle 348, inwardly facing flange 346 and one or
more tubes (gas delivery tube 304, a purge flow tube 310, material
delivery tubes 306, 308) may be fabricated from any material that
is non-reactive with the precursor and/or process gases provided to
the container 302, for example, such as quartz (SiO.sub.2).
[0036] In some embodiments, the bottom 332 of the container 302 may
comprise a plurality of through holes 340 configured to allow the
passage of gaseous precursor from the inner volume 338 of the
container 302 to an inner volume of a process chamber (e.g.,
reaction volume 101 of process chamber 100 described above).
[0037] The one or more solid precursor collection trays 312 are
disposed within the inner volume 338 of the container 302 and
generally comprise an inner baffle 314 having a plurality of slots
316, an outer wall 321 comprising a plurality of slots 313 and a
floor 344 coupling the inner baffle 314 to the outer wall 321. The
floor 344, inner baffle 314 and outer wall 321 form a storage area
342 to hold the precursor.
[0038] In some embodiments, the solid state material may be
provided to the one or more solid precursor collection trays 312
via one or more material delivery conduits (two material delivery
conduits 306, 308 shown). The precursor may be any solid state
material suitable to form a gaseous precursor to perform a desired
process. For example, in embodiments where a Group III-V
semiconductor material deposition process is performed on a
substrate disposed in a process chamber (e.g., substrate 125
disposed in process chamber 100 described above), the solid state
material may comprise an arsenic (As) precursor, such as arsenic
pellets, granules, or powder, or the like.
[0039] In some embodiments, one or more radiant heaters (one
radiant heater 320 per solid precursor collection tray 312 shown)
are disposed proximate the outer wall 321 circumscribing the one or
more solid precursor collection trays 312. In some embodiments, the
one or more solid precursor collection trays 312 may include a
flange 324 to support the one or more radiant heaters 320 (or the
floor 344 may extend radially beyond the storage area 342. The one
or more radiant heaters 320 may be fabricated from any material
suitable to transfer heat from a heat source (e.g., heating lamps
326 of the heater module 210) to the one or more solid precursor
collection trays 312. For example, in some embodiments, the one or
more radiant 320 heaters may be fabricated from silicon carbide
(SiC). In some embodiments, the temperature of the one or more
radiant heaters 320 may be monitored by a temperature monitoring
device, or sensor, (e.g., a pyrometer 328) disposed in the detector
module 212.
[0040] The heating lamps 326 may be any type of heating lamp
suitable to heat the one or more radiant heaters 320 to a desired
temperature. For example, in some embodiments, the heating lamps
326 may be similar to lamps utilized in a rapid thermal process
chamber (RTP) or an epitaxial (EPI) chamber. In such embodiments,
the lamps may have a capacity of up to about 650 W (e.g. such as
RTP process chamber lamps), or in some embodiments up to about 2 kW
(e.g., such as EPI process chamber lamps). Any number of heating
lamps 326 may be utilized in any configuration suitable to provide
adequate and efficient heating of the one or more radiant heaters
320. For example, in some embodiments, three heating modules 210
having one heating lamp 326 per solid precursor collection tray 312
may be disposed about the container 302, each heating module 210
separated from an adjacent heating module by about 60 degrees, such
as shown in FIG. 4. Alternatively or in combination, other heating
mechanisms may be utilized such as resistive heaters or heat
exchangers.
[0041] Referring back to FIG. 3, in some embodiments, one or more
of the one or more radiant heaters 320 may include a window 322 to
allow a line of sight to the one or more solid precursor collection
trays 312 from the detector module 212 to allow a temperature
monitoring device (e.g., a pyrometer 330) of the detector module
212 to detect the temperature of the one or more solid precursor
collection trays. In some embodiments, by monitoring the
temperature of the one or more solid precursor collection trays
312, the amount of material within the one or more solid precursor
collection trays 312 may also be monitored. For example, by
monitoring changes in light emissivity of the precursor detected by
the pyrometer 330, an amount of the precursor within the one or
more solid precursor collection trays 312 may be ascertained. Thus,
the detector module 212 may function as a precursor level
sensor.
[0042] The gas delivery tube 304 provides one or more gases to the
one or more solid precursor collection trays 312. The one or more
gases may be any gases suitable to perform a desired process, for
example such as a purge gas or carrier gas (e.g., a hydrogen gas,
nitrogen gas, or the like) or an etch gas (e.g., a halide
containing gas, such as hydrogen chloride (HCl), chlorine
(Cl.sub.2), hydrogen bromide (HBr), hydrogen iodide (HI), or the
like). In some embodiments, the gas delivery tube 304 may comprise
a heating element 318 disposed therein. The heating element 318 may
be any type of heating element, for example such as a silicon
carbide (SiC) radiant heating element to radiate heat absorbed from
a lamp heater (e.g., heating module 210). When present, the heating
element 318 provides control of the temperature of the gases
provided by the gas delivery tube 304. By controlling the
temperature of the gases provided by the gas delivery tube 304, the
inventors have observed that a reaction between the gases provided
by the gas delivery tube 304 and the precursor in the one or more
solid precursor collection trays 312 may be controlled, thereby
providing control over a concentration of the resultant process gas
to the process chamber. For example, in embodiments where a
hydrogen chloride gas and carrier gas is provided to an arsenic
containing one or more solid precursor collection trays 312 a
concentration of the resultant arsenic and halide gas
(AsH.sub.xCl.sub.y) gas may be controlled by controlling the
temperature of the hydrogen chloride gas and carrier gas via the
heating element.
[0043] The purge flow tube 310 provides a purge gas to the
facilitate purging of the container 302. In some embodiments, the
purge flow tube 310 may be positioned to provide a purge gas (e.g.
a hydrogen (H.sub.2) gas, nitrogen (N.sub.2) gas, or the like)
proximate the window 322 to maintain a line of sight, thereby
allowing the pyrometer 330 to take continuous accurate
measurements.
[0044] In operation of the apparatus 181 as described in the above
embodiments, the solid state precursor is provided to the storage
area 342 of the one or more of the solid precursor collection trays
312 disposed in the container 302 via the material delivery tubes
306, 308. The solid state precursor may be provided manually to the
material delivery tubes 306, 308, or in some embodiments via a
solid state precursor dispenser, as described below. Next, the
heating module 210 provides heat to the one or more radiant heaters
320 thus causing the one or more radiant heaters 320 to heat the
solid precursor collection trays 312. As the solid precursor
collection trays 312 are heated, the solid state precursor is
evaporated or sublimed, thus forming a gaseous state. Next, a gas,
for example, a carrier gas is provided to the solid precursor
collection trays 312 via the gas delivery tube 304. In some
embodiments, the gas provided by the gas delivery tube 304 may be
heated to a desired temperature via the heating element 318. The
carrier gas flows through the slots 316 of the inner baffle 314 to
the storage area 342, combines with the gaseous precursor and
carries the gaseous precursor through the slots 313 of the outer
wall 321 of the precursor tray 312 and out of the bottom 332 of the
container 302 and into the process chamber 100 (as indicated by
arrow 315). During operation of the apparatus 181, the amount of
solid state precursor material disposed in the solid precursor
collection trays 312 may be monitored via the pyrometer 330 of the
detector module 212 through the window 322 of the radiant heaters
320, 323. In some embodiments, when the amount of solid state
precursor material falls below a predetermined amount, a dispenser
(e.g. dispenser 500 described below) may automatically provide
additional solid state precursor material.
[0045] The inventors have observed that conventional systems used
to form gaseous precursors from solid state materials typically
utilize pre-filled sealed ampoules to contain the solid state
materials during the evaporation/sublimation process. However, when
the solid state material contained within the pre-filled ampoules
become exhausted the pre-filled ampoule must be removed from the
process chamber and replaced, thus leading to process downtime.
Moreover, the inventors have discovered that when using pre-filled
ampoules the solid state material may pack unevenly during
transportation or installation, thus leading to non-uniform gas
movement or gas channeling through the solid state material,
thereby causing to a non-uniform formation and/or dispersion of
gaseous precursor.
[0046] Accordingly, in some embodiments, the solid state precursor
source 173 source may comprise a precursor dispenser 500 configured
to provide the solid state precursor to the apparatus 181
(described above), for example as shown in FIG. 5. The precursor
dispenser 500 generally comprises a hopper 502 to hold the solid
state precursor, a valve 504 to control the flow of the solid state
precursor and a fill port 508 to dispense the solid state
precursor.
[0047] In some embodiments, the hopper 502 may be filled with the
solid state precursor in a hermetically sealed box (e.g., a glove
box) and then sealed under vacuum prior to use, thus eliminating
any direct contact an operator has with the solid state precursor.
The hopper 502 may be fabricated from any non-reactive material
suitable to hold the solid state precursor and maintain structural
integrity under vacuum. For example, in some embodiments the hopper
502 may be fabricated from quartz (SiO.sub.2).
[0048] The valve 504 may be any type of valve suitable to uniformly
disperse the solid state precursor, for example such as a plug
valve or ball valve. The fill port 508 may generally comprise a
tapered end 512 and a flange 510. In some embodiments, the tapered
end 512 is configured to interface with the material delivery tubes
306, 308 (described above) or an automatic dispensing mechanism
(e.g., dispensing mechanism 600 described below) and the flange 510
is configured to interface with an opposing surface to facilitate a
vacuum seal between the precursor dispenser and the surface (e.g.,
a surface of the dispensing mechanism 600 described below). In some
embodiments, a gas supply 506 may be coupled to the fill port 508
to provide a purge gas to the fill port 508. Providing a purge gas
(e.g., an inert gas such as argon (Ar), helium (He), or the like)
may facilitate continuous flow of the solid state precursor through
the fill port 512. The valve 504 and fill port 508 may be
fabricated from any material that is non-reactive with the solid
state precursor, for example such as stainless steel or quartz
(SiO.sub.2).
[0049] In some embodiments, the precursor dispenser 500 may further
comprise a dispensing mechanism 600, for example such as shown in
FIG. 6. When present, the dispensing mechanism 600 may provide the
solid state precursor to the apparatus 181 (described above)
automatically. By providing the solid state precursor
automatically, the inventors have discovered that possible exposure
of the operator to the solid state precursor may be reduced or
eliminated, thus making the process safer and more efficient. In
addition, providing the solid state precursor automatically may
reduce system downtime by providing the solid state precursor in
substantially constant amounts and by reducing exposure of the
solid state precursor to contaminants, thus maintaining a high
purity of the solid state precursor.
[0050] The dispensing mechanism 600 may be any type of material
dispenser suitable to provide the solid state precursor when
needed. For example, in some embodiments, the dispensing mechanism
600 may be a rotatable precursor dispenser, such as shown in FIG.
6. In such embodiments, the dispensing mechanism 600 may comprise a
body 610 containing a substantially circular hollow inner volume
611, an inlet port 614, a plug 613 disposed within the inner volume
611, and an outlet port 604.
[0051] The body 610 may be fabricated from any material that is
non-reactive to the solid state precursor, for example such as
stainless steel. The inlet port 614 is coupled to the inner volume
611 and, in some embodiments, may be configured to interface with a
fill port (e.g., fill port 512 described above). In some
embodiments, an o-ring 612 may be disposed about the inlet port 614
to facilitate a vacuum seal with an opposing surface, for example,
such as the flange 510 of the fill port 512 described above.
[0052] The plug 613 may be fabricated from any material that is
non-reactive to the solid state precursor and has a low coefficient
of friction to allow the plug to rotate within the inner volume 611
freely. For example, in some embodiments, the plug 613 may be
fabricated from a polymer such as polytetrafluoroethylene (PTFE).
The plug 613 comprises a first hole 615 and a second hole 617
formed therein, wherein the first hole 615 and second hole 617 are
fluidly coupled to one another. In some embodiments, a gas supply
608 is coupled to the inner volume 611 to provide pulses of inert
gas to the first hole 615 and second hole 617 to facilitate flow of
the solid state precursor and prevent packing of the solid state
precursor within the first hole 615 and second hole 617.
[0053] In some embodiments, a sensor 606, for example an optical
sensor or pressure sensor may be coupled to the outlet to
facilitate monitoring a pressure within the outlet 604 or the flow
of solid state precursor through the outlet 604. In some
embodiments, a gas supply 607 may be coupled to the outlet port 604
to provide pulses of inert gas to facilitate a flow of the solid
state precursor through the outlet port 604.
[0054] In some embodiments, a motor 702, for example, such as a
stepper motor, may be coupled to the plug 613 to control rotation
thereof, such as shown in FIG. 7. In operation of the dispensing
mechanism 600 as described in FIGS. 6 and 7, the solid state
precursor is provided to the inlet 614 from, for example, the
precursor dispenser 500. The solid state precursor flows into the
first hole 615 of the plug 613. The plug 613 is then rotated via
the motor 702 until the second hole 617 is aligned with the outlet
port 604. The gas supply 608 provides one or more pulses of gas,
forcing the solid state precursor to flow from the second hole 617
to the outlet port 604, thereby dispensing the solid state
precursor.
[0055] Returning to FIG. 1 to describe the remainder of the
exemplary process chamber 100, the substrate support 124 may be any
suitable substrate support, such as a plate (as illustrated in FIG.
1) or a ring (as illustrated by dotted lines in FIG. 1) to support
the substrate 125 thereon. The substrate support assembly 164
generally includes a support bracket having a plurality of support
pins coupled to the substrate support 124. The substrate lift
assembly 160 may be disposed about the central support 165 and
axially moveable therealong. The substrate lift assembly 160
comprises a substrate lift shaft 126 and a plurality of lift pin
modules 161 selectively resting on respective pads 127 of the
substrate lift shaft 126. In some embodiments, a lift pin module
161 comprises an optional base 129 and a lift pin 128 coupled to
the base 129. Alternatively, a bottom portion of the lift pin 128
may rest directly on the pads 127. In addition, other mechanisms
for raising and lowering the lift pins 128 may be utilized.
[0056] Each lift pin 128 is movably disposed through the lift pin
hole 169 in each support arm 134 and can rest on the lift pin
supporting surface when the lift pin 128 is in a retracted
position, for example, such as when the substrate 125 has been
lowered onto the substrate support 124. In some embodiments, such
as when the substrate support 124 comprises a plate or susceptor,
an upper portion of the lift pin 128 is movably disposed through an
opening 162 in the substrate support 124. In operation, the
substrate lift shaft 126 is moved to engage the lift pins 128. When
engaged, the lift pins 128 may raise the substrate 125 above the
substrate support 124 or lower the substrate 125 onto the substrate
support 124.
[0057] The substrate support 124 may further include a lift
mechanism 172 and a rotation mechanism 174 coupled to the substrate
support assembly 164. The lift mechanism 172 can be utilized to
move the substrate support 124 in a direction perpendicular to the
processing surface 123 of the substrate 125. For example, the lift
mechanism 172 may be used to position the substrate support 124
relative to the top gas injector 170 and the side gas injector 114.
The rotation mechanism 174 can be utilized for rotating the
substrate support 124 about a central axis. In operation, the lift
mechanism may facilitate dynamic control of the position of the
substrate 125 with respect to the flow field created by top gas
injector 170 and the side gas injector 114. Dynamic control of the
substrate 125 position in combination with continuous rotation of
the substrate 125 by the rotation mechanism 174 may be used to
optimize exposure of the processing surface 123 of the substrate
125 to the flow field to optimize deposition uniformity and/or
composition and minimize residue formation on the processing
surface 123.
[0058] During processing, the substrate 125 is disposed on the
substrate support 124. The lamps 152, and 154 are sources of
infrared (IR) radiation (i.e., heat) and, in operation, generate a
pre-determined temperature distribution across the substrate 125.
The chamber lid 106, the upper chamber liner 116, and the lower
dome 132 may be formed from quartz as discussed above; however,
other IR-transparent and process compatible materials may also be
used to form these components. The lamps 152, 154 may be part of a
multi-zone lamp heating apparatus to provide thermal uniformity to
the backside of the substrate support 124. For example, the heating
system 151 may include a plurality of heating zones, where each
heating zone includes a plurality of lamps. For example, the one or
more lamps 152 may be a first heating zone and the one or more
lamps 154 may be a second heating zone. Further, the lower dome 132
may be temperature controlled, for example, by active cooling,
window design or the like, to further aid control of thermal
uniformity on the backside of the substrate support 124, and/or on
the processing surface 123 of the substrate 125.
[0059] The support systems 130 include components used to execute
and monitor pre-determined processes (e.g., growing epitaxial
silicon films) in the process chamber 100. Such components
generally include various sub-systems. (e.g., gas panel(s), gas
distribution conduits, vacuum and exhaust sub-systems, and the
like) and devices (e.g., power supplies, process control
instruments, and the like) of the process chamber 100.
[0060] The controller 140 may be coupled to the process chamber 100
and support systems 130, directly (as shown in FIG. 1) or,
alternatively, via computers (or controllers) associated with the
process chamber and/or the support systems. The controller 140 may
be one of any form of general-purpose computer processor that can
be used in an industrial setting for controlling various chambers
and sub-processors. The memory, or computer-readable medium, 144 of
the CPU 142 may be one or more of readily available memory such as
random access memory (RAM), read only memory (ROM), floppy disk,
hard disk, or any other form of digital storage, local or remote.
The support circuits 146 are coupled to the CPU 142 for supporting
the processor in a conventional manner. These circuits include
cache, power supplies, clock circuits, input/output circuitry and
subsystems, and the like.
[0061] Thus, methods and apparatus for generating and delivering
process gases for processing substrates are provided herein. In
some embodiments, the inventive apparatus may advantageously
provide source materials (e.g. solid state precursors) necessary to
perform desired deposition processes while reducing or eliminating
exposure of the operator to the toxic materials, thus increasing
the safety and efficiency of the process. The inventive apparatus
may further advantageously provide an automatic feed of the source
materials, thereby reducing system downtime by providing the solid
state precursor in substantially constant amounts and by reducing
exposure of the solid state precursor to contaminants, thus
maintaining a high purity of the solid state precursor. Although
not limiting in scope, the apparatus may be particularly
advantageous in applications such as process chambers configured
for epitaxial deposition of Group III-V semiconductor materials,
for example, arsenic (As) containing materials.
[0062] While the foregoing is directed to embodiments of the
present invention, other and further embodiments of the invention
may be devised without departing from the basic scope thereof.
* * * * *